Two Early American Bomber Questions

[Noha307]

What was the purpose of the fin(s) on the top of the dorsal turret on the B-18?

Source: Me!

I remember reading somewhere (here?) about how it was tiring for World War I gunners to have to fight the air stream when rotating their gun, so maybe it has something to do with steadying the turret? Apparently, some Soviet turrets had something similar.

Similarly, what were the fins on the top of the rear of the engine nacelle on the B-10 for?

Source: http://www.aviation-history.com/martin/b10.html

Source: http://www.flickr.com/photos/govph/19282966912

I assume they were to keep the any flames coming out of the exhaust from blinding the pilot, but I'm not sure.

[shrike]

The fin on top (rear, really) of the turret balances the drag of the guns sticking out the front Yes, you can definitely feel the differences when manually cranking a turret around into the slipstream vs letting it blow the guns aft.